Price and where to buy? Does rotor from 21" wheel bolt right on? Plan to lower the rear shock if needed, then lower the front by using the 17" wheel. Options for four different drivers, 5' to 6' tall - 16 to 50 years. Would like to keep the 21" wheel-tire for logging trails while prospecting/hunting grouse woods. Trying to get the most use out of a multipurpose motorcycle.